fix: Don't access super property on implementation object

Accessing `super` here in CallbackHandlers::GetMethodOverrides() would
cause a new empty super object to be created, and try to copy the
implementation object's metadata node over to it. This would fail a DCHECK
because the metadata node is null.

Instead, since we are checking in the next line if the property value is
a function, and we know that the value of `super` isn't a function, we can
instead just skip `super`.

test-app/runtime/src/main/cpp/CallbackHandlers.cpp

@@ -634,6 +634,10 @@ CallbackHandlers::GetMethodOverrides(JEnv &env, const Local<Object> &implementat
     auto propNames = implementationObject->GetOwnPropertyNames(context).ToLocalChecked();
     for (int i = 0; i < propNames->Length(); i++) {
         auto name = propNames->Get(context, i).ToLocalChecked().As<String>();
+        if (name->StringEquals(V8StringConstants::GetSuper(isolate))) {
+            continue;
+        }
+
         auto method = implementationObject->Get(context, name).ToLocalChecked();
 
         bool methodFound = !method.IsEmpty() && method->IsFunction();